[Full-disclosure] Microsoft Windows Vista/2003/XP/2000 file management security issues

Michele Cicciotti mc at khamsa.net
Fri Mar 9 18:00:05 GMT 2007


>  Scenario  1.1:
> 
>  Bob  wishes  to  create "Bob private data" folder in "Public" folder to
>  place  few private files. "Public" has at least "Write" permissions for
>  "User" group. Bob:

This is, of course, wrong. You muddy the issue with the "Write permissions for User group" red herring and we are all supposed to oooh and aaah at your sleigh-of-hand trickery. Of course, a proper public repository for private folders should have saner settings than that, to begin with.

On my pet Windows Server 2003 machine, for example, I have created a "Protected" folder under "Shared Documents" (and why the hell don't server editions show "Shared Documents" under "My Computer" anyway?) before even thinking about sharing it, having recognized this risk scenario a long time ago ("what if a virus infected all those world-writable setup executables on public network shares?"); it's not really about "private" folders as much as "secure" folders with files that everyone can read but only the owner can write or delete

I have tried to create a "secure public" folder like the one you describe. Its ACL is a pretty complicated affair (not pictured: full access to Administrators and SYSTEM everywhere):
 * CREATOR OWNER: full access, subfolders and files, non-inheritable
 * Everyone: read-write, files only, non-inheritable
 * Everyone: read + create files + create folders, folder only
    = everyone can create files and folders

A file created under said folder gets the following default ACL: 
 * Everyone: read-write access
 * owner: full access
    = new files are public

A subfolder (or a subfolder of any subfolder) will get, instead:
 * CREATOR OWNER: full access, subfolders and files, inheritable
 * owner: full access, folder only, non inheritable
    = new folders are private

A file created inside a subfolder will get:
 * owner: full access
    = new files under private folders are private

Is this what you might be looking for?




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